Prostitutes are known for their skimpy attire, but Kenya's coastal port of Mombasa is witnessing a controversial fashion makeover.

The twilight ladies, as the city's residents refer to the sex workers, have traded their revealing outfits for the more austere buibui - a loose, floor-length gown and head covering favoured by Muslim women.

Walking along the city's main red-light streets at night, one comes across many of the buibui-clad prostitutes.

The buibui has lost its respect. I feel so embarrassed

Mariam SalmaMombasa resident

Although most shy away from speaking to the press, a few are willing to talk.

"I'm better off wearing the buibui so I look respectable. I can avoid arrest. I am just trying to get some money to live on," one says.

Another claims she wears her buibui to hide her identity.

"I know I am sinning, but I'm forced to because I am looking for my livelihood. So to me, it's acceptable," she says.

Most of her customers are local men, not tourists. She says wearing a buibui helped them to more easily pick out women from the region.

But the phenomenon is causing a stir in the predominantly Muslim city where religious women are required to cover their bodies from head to toe.

Some female residents say it is a big disgrace.

"I feel so embarrassed that sometimes I contemplate removing my buibui and throwing it away. The buibui has lost its respect," Mariam Salma says.

Another resident, Asha Hussein, claims the sex workers are not native to Mombasa.

"They are not Muslims. Most are from Somalia and Ethiopia. They wear it to avoid public humiliation," she says.

Crackdown

Wearing the buibui not only allows prostitutes to mingle freely with other women, black buibuis allow them to hide under the cover of darkness.

When night falls it is even easier for Mombasa's prostitutes to hide

City authorities have mounted numerous operations over the years to get prostitutes off the streets, with limited success.

After the crackdowns, the prostitutes go underground for a while, creating the impression that the operation has succeeded, only to emerge later.

The newly adopted attire has ensured their trade is not disrupted.

However, it is not the first time the prostitutes have used this tactic.

It was popular in the 1990s until a religious vigilante organisation illegally rounded up the prostitutes hiding under buibuis and flogged them publicly.

The uniform of prostitutes is well known. They should stick to their disgraceful attire

Sheikh Muhammad KhalifaCouncil of Imams of Kenya

Religious leaders are now urging the government to take action.

"We cannot arrest any of these women; it is the government's responsibility," says the organising secretary of the Council of Imams of Kenya, Sheikh Muhammad Khalifa.

"We are saddened because the government is ignoring the problem."

If the trend continues, police are likely to mistake respectable women for prostitutes, he says.

"For God's sake, if one has decided to join this profession, the uniform of prostitutes is well known.